The present invention relates generally to fences and, more specifically, to a fence employing a number of wires to which is attached an electrical sensing device.
There have been countless systems proposed for use in keeping unwanted persons or animals out of selected areas. Two approaches are popular in providing a fenced-in secure area, one such approach being a fence which actually physically excludes entrance from the area, e.g., a chain link fence, barbed wire fence, or the like. Another popular approach is to provide an electrified fence, wherein the fence is connected to a relatively high voltage which provides an electrical shock to a person or animal attempting to gain entry.
More recently, with the advent of more sophisticated electronic technology, security fences have employed proximity sensing systems and motion sensors. One approach is to utilize a magnetic field, produced by electrified fence wires, which is altered by the presence of a body. The altered magnetic field may be detected and used to indicate a possible intrusion. A similar approach is to use a capacitive field around the fenced area, alterations of which may also be sensed. The most popular approach is to use motion sensors attached to a chain link fence.
All of these present fences suffer from one or more drawbacks and, as may be expected, for every new kind of fence proposed, unscrupulous persons will devise methods for beating the security and entering the restricted area.
One of the principal drawbacks in most electrified systems which sense the presence of intruders is their high cost, both in initial cost and in installation costs. Additionally, they are generally very susceptible to false alarms and thus often require a full-time watchman in order to monitor the security system.
Therfore, there exists an almost ongoing need for improved security fencing systems, as well as a need to provide such systems at a resonably affordable cost.